Screen-plate for pulp-strainers.



I Patented July I, I902. u. L. VBUOMAN &. n. n. KIRKLAND-i '&CREEN PLATE FOB PULP' STRAINERS.

(Application filed m. 21, 1962.

(No Model.)

h esszs I UNITED STATES PATENT OFFICE.

NATHANIEL L. VROOMAN AND ROBERT R. KIRKLAND, OF W'ATERTOWN, NEW YORK.

SCREEN-PLAT E'FOR PU LP-STRAI N ERS.

SPECIFICATION forming part Of Letters Pateiht NO. 703,683, dated .11 uly 1, 1902.

Application filed February 21, 1902. 7 Serial No. 95,095. (N0 model.) I

To all whom it-nuty concern:

Be it known that we, NATHANIEL L. V1200- MAN and ROBERT R. KIRKLAND, citizens of the United States, residing at Watertown, in

the county of Jefferson and State of New York, have invented anew and useful Interchangeable Screen-Bar Plate for Pulp-Strainers, of which the following is a specification.

Our invention relates to certain improvements in the construction of devices employed for straining sulfite, wood-pulp, and other fibrous material employed in the manufacture of paper, and has for its principal object to provide an improved form of screenplate which may be employed in connection with pulp-strainers of the rotary,- diaphragm,

ent shape or'size to suit any class of work,'an'd to make any gage of screen desired.

A still further object of the invention is to provide for the rigid support of the interchangeable screening-bars in order to prevent any movement while in operation and. to keep the bars undera slight strain, -which will better enable them to remain inposition while under. working force. With these and other objects in View the invention consists in the novel construction and combination of parts hereinafter described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims.

In the drawings, Figure 11's a perspective view of a portion of a screen-plate constructed in accordance with ourinvention- Fig. 2 is a transverse sectional elevation-of the same on the line 2 2 of Fig. 1. Fig. 3 is a longitudinal sectional elevation of one end of the plate on the line3 3 of Fig. 2. Fig. 4 is a detail perspective view of one of the forms of interchangeable screen-bar which may be employed in the manufacture of the plate. Fig.

5 is a similar View of a slightly-differentform The main frame 10 of the plate is of rec tangular or such other form as may be required by the construction of the pulp-tank or the screening device or carrier with which the plate is employed. The frame may be cast in one piece or formed of sections and comprises side bars 11, an intermediate bar 12, substantially triangular in cross-section, and end bars 13. 'In Fig. 1' only one of the end bars is illustrated, it being understood that the plate may be of any required length and'provided at its opposite end with a similar integral bar. Theside bars 11 are considerably less in thickness than the end bars 13 and are adapted for the reception of clamping-bars 14E,whicli extend continuously from end to end of the frame and are secured to such side bars by lug-pins 15 and suitable securing bolts 16, arranged in countersunk openings in the side and clamping bars, the proportions being such that the combined thickness of the side an'd'clamping bars will be equal to the thickness of the end bars in order to give the frame a finished appearance and at the same time to prevent the passage of any unscreened stock.

In the inner edge portions of the side bars 11 areformed a series of equidistant V-shaped notches .17, and in similar manner the upper roundededge of the intermediate bar 12 is provided with similar notchesialining with those of the side bars. The notches 18 in the intermediate bar are of less depth than the notches 17, or they may be of the same depth, but arranged in a plane slightly above the plane of the notches of the side bars. I

The interchangeable screen; bars; 20 are formed of very hard drawn brassfor' bronze metal and may be of 'anyfsuitable shape in cross-section to accommodate any requirements of use, a preferable form for general Work being that illustrated in Fig. 4 and wherein each bar is of substantially V shape, being slightly rounded on top and having smooth hardened corners, which will materially reduce friction and lengthen the life of the bars, or the bars may have smooth flat upper surfaces, as shown in Fig. 5. At each end of the bar the upper surface is partly cut away, as indicated at 21, to provide a flat surface for contact with the lower and inner face of an inwardly-proj ectin g flange 22, forming part of the clamping-bars 14, the top of the screenbars when the latter are in position being flush with the surface of the clamping-bar and the flanges of the clamping-bars fitting snugly in the recesses formed in the ends of the screenbars to prevent the passage of unscreened stock.

In placing the screen-bars in position the series of bars are arranged parallel with each other in the alining notches 17 and 18; but as the notches 18 are a trifle above the plane of the notches of the side bars the latter will not be fully entered by the screen-bars. The clamping-bars are then placed in position and the bolts 16 are tightened until the ends of the screen-bars are firmly seated, the bars by this means being slightly arched or bowed, with the highest portion at the centerof the screenplate. By thus keeping the bars under a constant strain they may better resist any tendency of the passing pulp to move them from position, so that each bar will be rigidly held in place and the uniformity of gage preserved throughout the length of the plate.

\Vhen the bars become worn from constant use, they may be readily removed and new bars inserted or bars of difierent size or different shape may be substituted for those in the frame to accommodate any class of work and make any gage of screen desired.

The screening-surface comprises the entire area within the side and end bars, the shape of the intermediate bar being such as to interfere but slightly with the passage of the stock, such screening area being considerably greater than it is practicable to obtain with the solid sawed plates of the same size in ordinary use.

The supporting-frame will last for an indefinite period, and the only expense involved is the substitution of new screen-bars in order to produceapractically newplate. The screenbars, however, as a rule, will wear in a practically uniform manner, so that such bars may be used should it be necessary to form a screen-plate of wide mesh.

The plate as a whole may be employed in connection with pulp-strainers of any class, any suitable securing or supporting means being employed to hold it in position.

While the construction herein described and illustrated in the accompanying drawings is the preferred form of the device, it is obvious that various changes in the form, proportions, size, and minor details of the structure may be made without departing from the spirit or sacrificing any of the advantages of our invention.

Having thus described our invention, what we claim is-- 1. A screening device comprising a series of bars, and means for holding and supporting said bars in bowed position under a constant bending strain.

2. A screening device comprising a series of interchangeable screening-bars,devices for supporting the same, and means for clamping said bars in position and for slightly bending or bowing said bars.

3. A screening device comprising a frame and a series of interchangeable screeningbars held in said frame under a constant bending strain.

4. A screening device comprising a frame having a series of parallel supporting-bars having alining notches, the intermediate supporting-bars being arranged in a plane above that in which the outer supporting-bars are situated, and removable screen-bars carried by said supporting-bars.

5. The combination with a series of interchangeable screening-bars, of a frame comprising a series of notched supporting-bars adapted to receive the ends and intermediate portions of said screen-bars, the notches of the intermediate supporting-bars being arranged in the plane above the plane of the notches of the outer supporting-bars.

6. A screening device comprising a rectangular plate or frame having alining notches, a series of screen-bars disposed in said notches, the opposite ends of said screen-bars having reduced portions, and clamping-bars having flanges for engagement with said reduced portions.

7. A screening device comprising a frame having parallel side and intermediate bars each provided with notches or grooves, the bottoms of the notches or grooves of the intermediate bar being in a plane above the plane of the bottoms of the notches or grooves in the side bars, a series of screen-bars adapted to said notches, and means for confining the ends of said bars.

8. A screening device comprising a frame having parallel side and intermediate bars each provided with substantially V-shapcd notches or grooves, those of the intermediate bars being arranged in a plane above the notches of the side bars, a series of screenbars adapted to said notches, said screenbars having reduced end portions, and a flanged clamping-bar adapted for engagement with the reduced end portions of the screening-bars.

In testimony that we claim the foregoing as our own we have hereto afiixed oursignatures in the presence of two witnesses.

NATHANIEL L. VROOMAN. ROBT. R. KIRKLAND. Witnesses:

CHAS. S. KELLOGG, O. L. I'IILDRETH.

IIO 

